JPH064875A - Optical disk device and optical head - Google Patents

Abstract

(57) [Abstract] [Purpose] The lens actuator is structured so as not to be affected by the optical beam, and the size and cost of the lens actuator can be reduced, and the moving optical system and the fixed optical system can be achieved. It is an object of the present invention to provide an optical head that can shorten the optical path length between the optical head and the optical disk, is small in size, inexpensive, and has high performance, and an optical disk device equipped with the optical head. [Structure] A lens actuator 16 is replaced with an objective lens 15
So that the lens holding portion 20 for holding the optical disc 10 is located in a direction closer to the fixed optical system 70 side, that is, the movable side support member 25 is in the outer diameter direction of the optical disk 10 and the fixed side support member 2.
6 is incorporated in the optical head 1 so that the optical disc 6 is located in the inner diameter direction of the optical disc 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for irradiating an optical disk, which is an information storage medium, with a light beam for information processing, and an optical head used in the disk device.

[0002]

2. Description of the Related Art Generally, in an optical disc apparatus, a movable optical system such as an objective lens and a start-up mirror is mounted on an optical head movable along the radial direction of the optical disc, and is fixedly provided. It is configured to exchange a light beam (laser beam) with the optical system. The fixed optical system is provided on an extension line of the movement path of the optical head in the outer peripheral direction of the optical disc.

The optical laser from the fixed optical section is irradiated horizontally along the moving direction of the optical head, vertically raised by a raising mirror mounted on the optical head, and then provided above this. It is focused by the objective lens and irradiated onto the information recording surface of the optical disc. Further, the reflected light from the information recording surface follows a path opposite to the above path and returns to the fixed optical system.

On the other hand, the objective lens is supported by a lens actuator having a lens holding portion so as to be movable in a direction (focus control direction) in and out of contact with an information recording surface of the optical disk, and the surface of the optical disk is supported. The objective lens can be focused by following the shake and the like.

A lens actuator usually has a movable side supporting member having a lens holding portion, a fixed side supporting member fixed to an attached portion formed on a carriage movable in a radial direction of an optical disk, and a fixed side supporting member. It is composed of two upper and lower parallel leaf springs connected to each other.

Conventionally, the lens actuator is mounted on the optical head such that the movable side support member is located in the inner diameter direction of the optical disk and the fixed side support member is located in the outer diameter direction of the optical disk. In other words, the lens holding part is mounted on the optical head in a state of being distant from the fixed optical system side, and the light beam passes between the upper and lower two parallel leaf springs.

However, in such a structure, the distance between the two parallel leaf springs takes into consideration the amount of displacement in addition to the beam diameter so that the beam diameter does not depend on the movement of the leaf spring in the focus direction. The size must be set, which hinders the thinning of the lens actuator and thus the thinning of the optical disk device itself.

Further, since the fixed side supporting member is located on the side of the fixed optical system, a through hole through which the optical beam passes must be formed in the fixed side supporting member, and the lens actuator is integrally molded. In this case, there is a problem that the structure of the molding die becomes complicated and the manufacturing cost becomes high.

Further, in the conventional apparatus, when the objective lens reaches the outermost peripheral position of the optical disk, the parallel plate spring and the fixed side supporting member for holding the parallel plate spring are located further outside, so that the fixed optical system is provided. Was further outside and had a long optical path. Therefore, there is a problem that the amount of deviation between the optical axes of the incident light and the reflected light cannot be reduced, which becomes an obstacle in performing highly accurate information processing. The shift amount of the optical axis is expressed by the following equation.

That is, as shown in FIG. 5, an optical beam B reflected by a galvano mirror A of a fixed optical system is passed through a rising mirror C of a moving optical system and an objective lens (focusing lens) D to an optical disk. In the configuration leading to E, f: focal length of the objective lens D, d: shift amount of the optical axis, L ₁ : distance between the rising mirror C and the objective lens D L ₂ : galvano-mirror A and rising mirror C Assuming that the distance is d = 2 · Δd {(L ₁ + L ₂ / f) −1}.

As is apparent from the above, when the galvanometer mirror A is rotationally displaced to change the beam angle to swing the beam in the tracking direction (radial direction) of the optical disc E, the longer the optical path length is, the more the incident light becomes. The shift amount d of the optical axis of the reflected light becomes large.

[0012]

As described above, in the conventional optical head, the optical beam passes between the parallel leaf springs, so that the lens actuator cannot be thinned. Since the through hole through which the optical beam passes must be formed in the fixed side supporting member, the manufacturing cost becomes high. Moreover, there is a problem that the optical path length between the moving optical system and the fixed optical system is inevitably long, the amount of deviation between the optical axes of the incident light and the reflected light becomes large, and the information processing accuracy is impaired. Further, the optical disk device using this has the same problem.

The present invention has been made based on the above circumstances, and the lens actuator can be downsized and the cost can be reduced as a structure in which the lens actuator is not affected by the optical beam. It is an object of the present invention to provide a small-sized, inexpensive, and high-performance optical head capable of shortening the optical path length between the moving optical system and the fixed optical system, and an optical disk device equipped with the optical head.

[0014]

The present invention provides an optical disk device for solving the above-mentioned problems, and a disk drive means for holding and rotating an optical disk, and a light beam to the optical disk rotated by the disk drive means. A lens that has a lens holding portion that holds the objective lens and that is connected to a supporting member via a moving optical system including an objective lens for condensing and an elastic supporting plate and that supports the lens holding portion so as to be movable in the optical axis direction thereof. An optical head equipped with an actuator and movable along the radial direction of the optical disc; and the moving optical system mounted on the optical head provided on an extension line of the movement path of the optical head in the outer peripheral direction of the optical disc. An optical disc device comprising a fixed optical system for transmitting and receiving a light beam, wherein the lens actuator is the objective lens. Those incorporated in the optical head such that the lens holding unit for holding is located near becomes direction to the stationary optical system side.

Further, as an optical head for solving the above-mentioned problems, an objective lens for converging a light beam on an optical disk and a lens holding portion for holding this objective lens are provided, and the lens holding portion is provided with the light of the objective lens. A lens actuator that is movably supported in the axial direction, a carriage that mounts the lens actuator and is movable along the radial direction of the optical disk, and the lens that is movably supported by the lens actuator. An optical head comprising a lens driving means for moving a holding part in the optical axis direction of an objective lens, wherein the lens actuator has a movable side supporting member having the lens holding part, and the movable side supporting member. A fixed side support member which is fixed to a mounted portion formed on the carriage at a certain distance from the member; It comprises two parallel elastic support plates integrated so as to connect to the movable side support member, wherein the fixed side support member is in the inner diameter direction of the optical disc and the movable side support member is in the outer diameter direction of the optical disc. It is mounted on the carriage so as to be located at.

[0016]

In the optical disk device and the optical head described above, the lens actuator is positioned so that the lens holding portion for holding the objective lens is close to the fixed optical system side, that is, the movable side support member. Is incorporated in the optical head so that the fixed side support member is positioned in the outer diameter direction of the optical disk and the fixed side support member is positioned in the inner diameter direction of the optical disk. Therefore, the fixed side support member and the two parallel elastic support plates are irrespective of the optical beam position. Can be placed. This allows the lens actuator to be made thinner. Further, it is not necessary to form a through hole through which the optical beam passes in the fixed side supporting member, and when the lens actuator is integrally molded, the structure of the molding die becomes simple and the manufacturing cost can be reduced. Become.

Further, since the fixed optical system can be arranged at a position closer to the outermost peripheral position of the optical disc, the optical path length can be shortened and the deviation amount of the optical axes of the incident light and the reflected light can be reduced as compared with the conventional case. Therefore, highly accurate information processing becomes possible.
As a result, it is possible to provide a small-sized, inexpensive, and high-performance optical head and an optical disk device equipped with the optical head.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, with reference to FIG. 1 and FIG. 2, there is schematically shown a configuration of a main part of an optical disk device, in which a spindle as a disk drive means for holding and rotating an optical disk 10 which is an information storage medium. A motor 50, a moving optical system 60 including an objective lens 15 for converging a light beam (laser beam) LB on the optical disk 10 rotated by the spindle motor 50, and the objective lens 15 are held. And an optical head 1 having a lens actuator 16 for movably supporting the optical axis direction and capable of moving the lower surface side of the optical disk 10 along its radial direction.
A laser beam LB as a light beam and the moving optical system 60 mounted on the optical head 1 which is provided on an extension line of the movement path of the optical head 1 in the outer peripheral direction of the optical disk 10.
And a fixed optical system 70 for transmitting and receiving.

The spindle motor 50 magnetically attracts and holds a metallic hub portion (not shown) provided at the center of rotation of the optical disk 10 and also holds the optical disk 10.
And a motor 52 for driving the turntable 51. Also,
As shown in detail in FIG. 3, the optical head 1 has a carriage 3 which is reciprocally provided in the direction of arrow A by two guide shafts 2 and 2.

The carriage 3 includes a guide shaft 2 and
2 and the guide shaft (yaw)
) By a linear motor 6 including magnets 4 and 4 provided in parallel with 2, 2 and coils 5 mounted on bearings 3a, 3a, 3b and 3b of the carriage 3, the direction of the arrow A, that is, Optical disc 1 which is an information storage medium
It moves in the radial direction of 0 (track control direction). The carriage 3 includes a lens actuator 16 holding an objective lens 15 and a start-up mirror 17.
(See FIG. 1).

A moving optical system 60 composed of the objective lens 15 and the start-up mirror 17 and a fixed optical system 70 provided on an extension line of the optical head 1 in the outer peripheral direction of the moving path of the optical head 1. Laser beam LB between
It is designed to give and receive.

The fixed optical system 70 is a semiconductor laser (not shown).
The moving optical system 60 includes optical members such as a lens, collimator lens, beam splitter, and galvano mirror.
Is a laser beam LB guided from the fixed optical system 70.
Of the laser beam LB reflected from the optical disc 10 onto the information recording surface of the optical disc 10 or the fixed optical system 70.
It is supposed to return to. The laser beam LB returned to the fixed optical system 70 is guided to an information detecting detector, a focusing detector, and a tracking detector (not shown).

The lens holding portion 20 of the lens actuator 16 which holds the objective lens 15 is provided with a lens
The scrap control coil 21 is closely fixed, and the carriage 3 is provided with magnets 22, 2 for providing a magnetic field in a desired direction toward the focus control coil 21.
2 are arranged respectively. Then, the objective lens 15
Lens driving means 23 for moving the lens holding portion 20 holding the optical disk in the direction of arrow B, that is, in the direction of moving toward and away from the optical disc 10 (focus control direction).

Further, the lens actuator 16 is
As shown in FIG. 4, a resin movable side support member 25 having the lens holding portion 20, and the movable side support member 25.
A fixed side supporting member 26 made of resin, which is fixed to the mounted portions 3c, 3c formed on the carriage 3 with a certain distance, and the fixed side supporting member 26 and the movable side supporting member 25. It is composed of parallel first and second elastic support plates 27 and 28 which are plate springs integrally formed with these to be connected.

The first elastic support plate 27 located on the upper side is
2 between the fixed side support member 26 and the lens holding portion 20.
The book has arm shapes 27a, 27a. Further, the second elastic support plate 28 located on the lower side is provided between the fixed side support member 26 and the movable side support member 25 and in the middle of the two arm portions 27a, 27a.
The shape is such that the arm part 28a of the book exists.

The movable side support member 25 having the lens holding portion 20 on the upper end side is in the form of a strip plate whose vertical direction is the longitudinal direction, and is formed along the vertical direction on the rising wall 3d of the carriage 3. It is interposed in the groove 30 so as to be vertically movable. Unnecessary movement in the lateral shake direction is restricted by the groove 30.

On the other hand, the fixed side support member 26 is formed in a plate shape, and has arcuate positioning projections 3 on the front surfaces of both side ends thereof.
It has 1,31. Then, these positioning protrusions 3
1 and 31 are attached parts 3 formed on the carriage 3
The positioning with respect to the carriage 3 is performed by engaging with the arcuate positioning grooves 32 and 32 of c and 3c. Further, the fixed side support member 26 is integrally fixed to the carriage 3 by being adhered and fixed by an adhesive in a positioned state.

Further, the lens actuator 16 thus constructed is positioned in a direction in which the lens holding portion 20 holding the objective lens 15 is close to the fixed optical system 70 side, as shown in FIGS. In other words, the movable side supporting member 25 is incorporated in the optical head 1 so that the movable side supporting member 25 is positioned in the outer diameter direction of the optical disk 10 and the fixed side supporting member 26 is positioned in the inner diameter direction of the optical disk 10.

Therefore, according to the present invention,
Two elastic support plates 27, 2 parallel to the fixed-side support member 26
8 is arranged on the inner diameter side of the optical disk 10 and a laser beam LB between it and a fixed optical system 70 provided on the outer diameter side.
The shape is not affected by the incident light and the reflected light. Therefore, the lens actuator 16 can be thinned. Also,
It is not necessary to form a through hole through which the laser beam LB passes in the fixed side support member 26, and when the lens actuator 16 is integrally molded, the structure of the molding die is simplified and the manufacturing cost is reduced. It will be possible.

Further, the fixed optical system 70 is connected to the optical disk 10.
Since it can be arranged at a position closer to the outermost peripheral position of, the optical path length can be shortened and the amount of deviation of the optical axes of the incident light and the reflected light can be made smaller than in the conventional case, and highly accurate information processing becomes possible. . It should be noted that the present invention is not limited to the above-described one embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0032]

As described above, according to the present invention, the lens actuator can be downsized and the cost can be reduced as the structure in which the lens actuator is not affected by the optical beam. The optical path length between the moving optical system and the fixed optical system can be shortened, and it is possible to provide an optical head that is small in size, inexpensive, and has high performance, and an optical disk device equipped with the optical head.

[Brief description of drawings]

FIG. 1 is a side view schematically showing a configuration of a main part of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a perspective view schematically showing the configuration of the main part of the optical disc device.

FIG. 3 is a perspective view showing an embodiment of the optical head of the present invention.

FIG. 4 is an exploded perspective view of a main part of the optical head in the example.

FIG. 5 is an explanatory diagram showing a relationship between an optical path length and an optical axis shift.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical head, 2 ... Guide shaft, 3 ... Carriage, 6 ... Linear motor, 10 ... Optical disk, 15 ... Objective lens, 16 ... Lens actuator, 17 ... Startup mirror, 20 ... Lens holding part, 21 ... Focus control coil, 22 ... Magnet, 23 ... Lens driving means, 25 ...
Movable side support member, 26 ... Fixed side support member, 27 ... First elastic support plate, 50 ... Spindle motor (disk drive means), 60 ... Moving optical system, 70 ... Fixed optical system, LB ... Laser beam -Mem (light beam).

Claims (2)

[Claims] 1. A disk drive means for holding and rotating an optical disk, and a movable optical system including an objective lens for focusing a light beam on the optical disk rotated by the disk drive means and a support through an elastic support plate. An optical system that has a lens holding unit that is connected to a member and holds the objective lens, and that has a lens actuator that movably supports the lens holding unit in the optical axis direction and that is movable along the radial direction of the optical disc. An optical disk device comprising a head and a fixed optical system for transmitting and receiving a light beam to and from the moving optical system mounted on the optical head, the fixed optical system being provided on an extension line of an optical disk in a movement path of the optical head. And the lens actuator is positioned in a direction in which the lens holding portion holding the objective lens is close to the fixed optical system side. An optical disk device characterized by being incorporated into an optical head. 2. A lens actuator which has an objective lens for converging a light beam on an optical disc, and a lens holding portion for holding the objective lens, the lens holding portion movably supporting the objective lens in the optical axis direction of the objective lens. A carriage that mounts this lens actuator and is movable in the radial direction of the optical disk; and a lens holder that is movably supported by the lens actuator in the optical axis direction of the objective lens. An optical head comprising: a lens driving unit for driving the lens holder, wherein the lens actuator has a movable side supporting member having the lens holding portion, and has a certain distance from the movable side supporting member. A fixed-side support member fixed to a mounted portion formed on the carriage, and an integrated unit for connecting the fixed-side support member and the movable-side support member Two elastic support plates are mounted on the carriage so that the fixed-side support member is positioned in the inner diameter direction of the optical disk and the movable-side support member is positioned in the outer diameter direction of the optical disk. Characteristic optical head.